Object gets darker when I zoom in to the object
It looks like you have a Point light (or maybe a Spot) as light source in your scene. If it were a Sun than a value of 40 would be extremely bright, also a sun's strength value would be shown as a decimal 40.000 without a W for watts.
Go to the light settings and switch from Point (or Spot) to Sun. Or delete the light source and add a new Sun.